I been having this problem for about 4 months now. The car starts when it wants to, and then when it is running it will drop down to running on 4 cylinders. Enigine info is 385ci 1985 MAF TPI setup 12:1 Compression. Today I was messing around with it cuz I had some free time. So I pulled a couple of plugs to see how they were sparking. I observed that the spark was variable. The spark went from no spark, to a dim spark, and sometimes there was a really bright spark. So every 8-12 Motor Rotations I would get a good spark and the motor would want to fire but as soon as it wants to fire it stops. New parts: Brand new distributor, ESCM, good working ecm, new 50,000 volt coil. Anyone have any ideas what would be causing my spark to not enough to no spark problem. Could it be a fusible link, I check all my other fuse, I just dont see it being a fusible link since I do have spark at some point. Battery had tested and it checks out good and so does my Alternator. Would MSD be a possibility to bypass or end my problem?

Help is greatly appreciated Thanks

 

Anyone? Any suggestion may help.

 

Would a bad voltage regulator, or alternator cause this kind of problem, all my ground are good.

Installed MSD today, Car did start but took awhile for it to get going but now fires right up as for now, but still seems like battery wants to die, I did have the battery and alternator checked and they both check out good, but when they check the alternator do they also check the voltage regulator?